Piezo-electric properties of polypropylene laminates with a non-woven layer

Piezoelectric properties of non-uniform dielectric structures with an elastic layer made of polypropylene unwoven fabric are presented. The properties were characterised by d33 piezoelectric coefficient, measured as a function of pressure p applied to the structure. A hyperbolic type of d33 = f(p) dependence was found for prepared samples. A new model describing d33 = f(p) dependence observed for the structures has been proposed. Linear dependence of elasticity modulus on pressure p has been assumed in the model. The d33 values determined on the basis of the model were compared with experimental data and a good agreement was found.